Mazda 626 Station Wagon, Workshop Manual

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ON-BOARD DIAGNOSTIC
DTC P0135
Except for GF4A-EL Models
DTC P0135
H02S heater circuit malfunction
DETECTION
CONDITION
• PCM monitors H02S heater control signal at PCM terminal 94. If PCM turns H02S heater on and off
but voltage at PCM terminal 94 does not change, PCM determines that H02S heater circuit has
malfunction.
POSSIBLE
CAUSE
• H02S malfunction
• Open circuit between the main relay terminal D and H02S terminal C
• Open circuit between the H02S terminal D and PCM terminal 94
• Short to ground circuit between H02S terminal D and PCM terminal 94
• Poor connection at H02S or PCM connector
• PCM malfunction
IG1
t r ~ ------^
c
D
r
PCM
l | l |l | l , l | l | l , l |l , l |l . l I I I I . 1 J I I . M . I . I . I . M .
HARNESS SIDE C O N NECTO R
(V IE W FROM TER M IN A L SIDE)
94
HARNESS SID E CO NNECTO R
(VIEW FROM TERM INA L SIDE)
Diagnostic procedure
STEP INSPECTION ACTION
1 VERIFY RELATED REPAIR INFORMATION
AVAILABILITY
• Check for related Service Information
availability.
• Is any related Service Information available?
Yes Perform repair or diagnosis according to available
Service Information.
• If vehicle is not repaired, then go to next step.
No Go to next step.
2 INSPECT POOR CONNECTION OF H02S
CONNECTOR
• Turn ignition key to OFF.
• Disconnect H02S connector.
• Check for poor connection (damaged,
pulled-out terminals, corrosion, etc.).
• Are there any malfunctions?
Yes Repair or replace terminal, then go to Step 9.
No Go to next step.
3 INSPECT H02S HEATER
• Measure resistance between H02S terminals
C and D (part-side).
• Is there resistance within 5.0— 6.8 £ 2?
Yes Go to next step.
No Replace the H02S, then go to Step 9.
F1-59